In the field of semiconductor manufacturing, as well as other fields, a plasma chamber has various possible uses. For example, plasma-enhanced chemical vapor deposition (CVD) is a process used to deposit thin films on a substrate using a plasma chamber. In high level terms, a radio frequency (RF) power supply generates a plasma from reacting gases, within the chamber, and from which the deposition occurs on a substrate within the chamber. In order to achieve efficient power transfer between an RF generator and the plasma load, an impedance-matching network is often used to match the load impedance (including the impedance of the plasma) to the output impedance of the power supply. The load impedance is typically around 50 Ohms but it varies. For example, plasma load impedance may vary depending on variables such as generator frequency, power, chamber pressure, gas composition, and plasma ignition. The match network accounts for these variations in load impedance by varying electrical elements, typically vacuum variable capacitors, to match the varying load impedance to the generator's output impedance.
Recent developments in plasma generating techniques have involved multi-level pulsing of the RF energy that tailors or otherwise customizes the plasma characteristics, as one example, time-dependent behaviors, in the plasma chamber. In general, multi-level pulse generally involves cyclic adjustment of the intensity level of RF energy inputted into the plasma chamber using two or more amplitude levels of the RF generator such that an optimum profile of the ions and free radicals both in the bulk of the plasma and those arriving to the surface of a substrate may be provided over a desired period of time. Using multi-level pulse plasma generating techniques, enhanced etch and CVD results can be realized, among other various benefits.